Double-acting centrifugal pump



Feb. 15, 1949. D MURPHY 2,461,835

DOUBLE-ACTING CENTRIFUGAL PUMP Filed April 18, 1944 3 Sheets-Sheet 1 INVENTOR Daniel Murphy Feb. l5, 1949- D. MURPHY DOUBLE-ACTING CENTRIFUGAL PUMP Filed April 18, 1944 3 Sheets-Sheet Feb. 15, 1949. D MURPHY 2,461,835

` DOUBLE-ACTING CENTRIFUGAL PUMP Filed'April 1s, 1944 3 sheets-sheet s 'll/l E Daniel Murphy Patented Feb. 15, 1949 UNITED STATES PATENT OFFICE DoULE-Acrmd cEN'rmFUGAL PUMP Daniel Murphy, New Castle, Pa.

Application April 1s, 1944, serial No.` 531,546

(ci. los-104) 7 Claims.

My invention relates to centrifugal pumps, particularly to self-priming pumps of the type disclosed in Letters Patent No. 2,179,858 granted to me on November 14, 1939.

The impeller of such pump comprises a disklike rotor carrying integrally on one of its opposite faces a plurality of curved vanes whose otherwise free edges cooperate with the face of a stationary wearing plate to form, in conjunction with the spaces between the vanes, radially extending involute passageways. When the impeller is in rotation, the uid being pumped enters these passageways at their inner ends, and under the centrifugal effect the iuld is forced outward through the outer ends of the passageways into the outlet duct of the pump. More particularly, my invention consists in a doubleacting pump of this class, a pump in which the pump impeller carries a set of vanes on each of its opposite sides, and is provided with two stationary wearing plates, one for each set of vanes.

'I'his double-acting pump is advantageously,v

though not necessarily, of the self-priming type.

The double-acting pump of my invention provides in a unit of given size almost twice the capacity of a single-acting pump, and it is effective to deliver the'pumped duid at much higher pressure. In a hydraulic pump embodying the invention, I have obtained a delivery head as high as eighty-four pounds per square inch.

One of the problems in the construction of double-acting pumps of the vaned impeller type has been the provision of suitable means for the ready adjustment of the side walls, or of the wearing plates mounted in the side walls, relatively to the edges of the impeller vanes, to compensate for the wear that occurs between such edges of the vanes and the wearing plates or side walls, the wear being particularly acute in those installations in which the liquid being pumped carries abrasive particles; for example, the slip which is pumped in potteries."

It has been the practice in the past to divide the impeller housing on an axial plane (axial with respect to the impeller `axis), and to take the housing apart when it was necessary to make an adjustment of the wearing plates. In accordance with my invention, I provide a structural arrangement that admits of the ready adjustment for wear, without the necessitv of taking the impeller housing apart. Additionally, the double-acting pump of the invention is adapted to utilize the particularly effective impeller-shaft bearing disclosed in my co-pending application. Serial No. 477,703. filed March 2. 1943, now matured into Letters Patent No. 2,355,- 390 of August 8, 1944 together with the impellershaft seal illustrated and described in mv copending application Serial No. 521,771, filed February 10, 1944 now matured into Patent 2,453,- 249 of November 9, 1948.

The invention will be understood upon reference to the accompanying drawings, in which:

'Figure 1 is a view in end elevation of a pump embodying the invention;

Figure 2 is a view of the pump in perspective;

Figure 3 -is a view of the pump impeller in side elevation and to larger scale;

Figure 4 is a fragmentary view oi the pump to still larger scale, showing the portions of the structure in which the invention is centered, the view being` partly in side elevation and partly in vertical section; and

Figure 5 is afragmentary sectional view of a portion of the structure shown in Figure 4, and serves to illustrate one of the permissible modications in the pump of the invention.

Referring to the drawings, the pump consists in a pump body or housing 2 including an inlet chest 3 that has therein a chamber 4, in which a rotary impeller 5 is supported upon the end of a shaft 6. The inlet chest I extends downward on opposite sides of the impeller chamber, as shown. The pump body includes an inlet passage I that extends downward into the inlet chest 3, and inlet communication between the inlet chest and the central region of the impeller chamber is provided by means ofinlet ports 8 and 9 formed concentrically with the impeller axis in wearing plates III and II. These plates comprise combination inlet and wear 'plates which, as will later appear, provide the oppositev side walls of the impeller chamber. From the"` impeller chamber I an outlet passage I2 (Figure 4) extends upward to a receiver chamber I3 (Figures 1 and `2) included in the delivery line I4 leading from the pump. TheA shaft 6 extends from the pump housing and is coupled to means for powerfully rotating it, such means in this case consisting of an electric motor I5.

When the pump is in operation, the liquid being pumped is drawn upward through a conduit I6 from a source of supply. Included in the line of ilow from conduit I 6 to inlet passage 1 is a check-valve I1. which is located at a higher elevation than the impeller chamber 4, as also is the receiver chamber I3, in the discharge line of the pump. And the discharge line ordinarily Will, as herein shown, include a checkvalve I8.

On the pump side of the inlet check-valve I1 a by-pass I9 (Figure 1) of relatively small cross section opens from the receiver chamber I3 at a point adjacent the bottom thereof. When the impeller 5 is set in rotation and comes up to speed. liquid is drawn upwardv through conduit I6; the upsurging liquid opens the check-valve. as may be fully understood upon reference to my said Letters Patent No. 2,179,858. In the usual installation the pump is arranged above the source of liquid being pumped, and it is in such installations that a rotary pump tends to become gas-bound and requires priming` but by virtue of the structure disclosed in said Letters Patent and embodied in the `pump herein described, the pump does not become gas-bound, and once the pump has been installed and operated it need never be primed, no matter how often it is shut down and started up. Always there is enough liquid retained in the inlet chest 3 and inlet passage 1 of the pump to initiate effective pump operation, it being noted that the check-valve l1 closes and prevents back syphonage of liquid when the pump is shut down, and the receiver chamber I3 feeds back enough liquid through by-pass I9 to insure that the pump shall always be primed for startinf.l up.

The housing 2 of the pump includes a portion 2a, and with such housing portion two bearings for the shaft 6 are organized, the bearings being spaced apart longitudinally ofthe shaft to prevent whipping of the shaft when the pump is in operation. One of the bearings consists of concentric rings 23 and 24 with rolling members, here shown to be balls 25, arranged in the race formed for them by and between the rings. The inner ring 23 is securely locked on the shaft E by means of a drift fit or the like, while the outer ring 24 is housed within the internally threaded hub por` tion 23 of a spider 2| that is secured to the housing portion 2a by means of screws 22. The bearing is held against axial displacement between two nuts 21 and 28, that, encircling the shaft 6 and movable therealong, engage the threads of the hub portion, as illustrated in Figure 4. The open structure of the spider 2| gives access to l the nut 21 for adjusting it axially of the shaft,

and a lock-screw 29 is provided for securing the nut in adjusted position. The nut 28 is accessible for adjustment at the open end of the hub portion 2B, and manifestly, by the mutual adjustment of the nuts 21 and 28, the bearing may be axially shifted. Due to the locked engagement of the inner bearing ring 23 with the impeller shaft 6, this shifting of the bearing is effective axially to adjust the impeller shaft, for reasons presently to be described.

The other of the two bearings for the impeller shaft comprises a block held in place in the cylindrical bore of the housing portion 2a by means of the spider 2|. Within the block 20 a sleeve portion 39 is bushed with a bronze liner 3| that provides the immediate bearing for the shaft. The bore of the block 20 provides at its outer end a stuing box for the shaft; that is to say, the space formed by and between the block and the shaft and the end of the bronze-lined sleeve 30 provides a stuiilng box in which are arranged bodies 32 of packing with an interposed lantern ring 33. The stuffing box is closed at its outer end by a packing gland 34, drawn tight and secured upon the packing 32 by means of screws 35 in threaded engagement with the block 20. The block 20, the bronze-lined sleeve 30,- and the lantern ring 30 are formed with a system of pas,-

sages 36 through which lubricant may be fed from a cup 31 to the lantern ring and packing, and to the bronze bushing 3| that provides the immediate bearing for the shaft within the block 20.

It is requisite that provision be made against Withdrawal of lubricant from the bearings by the suction of the pump in operation, and, when the pump is at rest, against ingress to the bearings of the liquid that is pumped, a supply of which remains standing in the inlet chest 3. An annular shaft-encircling plate 38 is, by the block 20 under the effect ofscrews 22, clamped with sealing effect to the `right-hand end (Figure 4) of the cylindrical bore in the housing portion 2a, and the annular plate is in this case shown to be integral with the sleeve 30. A shaft-encircling member 39 projects from the plate, and in the assembled pump it extends through the orifice in the pump wall formed for the passage of thc impeller shaft 6. The member 39 is designed for diminution of friction in the rotation of an adjacent body rotating in abutment upon it, and to such purpose it is formed of Babbitt metal and is tightly assembled with the plate. Alternatively, the member 39 may be integrally formed with the plate and provided at its extremity (to the right) with bores which, as described in my said co-pending application Serial No. 521,771, are filled with a material of lubricating characteristics, such as graphite or Ba-bbitt metal.

A sealing device cooperates with the shaft-encompassing member 39 to prevent liquid from being sucked into the pump from the bearing structure when the pump is in operation, and to prevent liquid from draining from the pump Ainto the bearing structure when the pump is at rest. The sealing device comprises a collar portion 40 keyed to the shaft 4, while being adapted to slide on the shaft to maintain snug contact with the self-lubricating face or edge of the stationary member 39.

Organized with the collar portion 40 is a tubular member 4| formed of exible and elastic material that is resistant to deterioration under the effects of the liquid being pumped and of the lubricant used in the bearing structure. A synthetic rubber known on the market as neoprene has been found to be a suitable material of which to form the member 4|. At one end of its tubular or ring-like body the member 4| is secured in sealed union to the collar portion 40, and at opposite end is secured in sealed union to the shaft, or to a portion that is united to the shaft in such way that the effect is the same. For example, a collar 42, backed by a compressed spring 43, may be adapted to seal the right-hand end (Figure 4) of the member 4I to the shaft, as taught in my said application Seria-l No. 521,771. The assembly is adapted to permit axial movement of the said collar portion on the shaft without breaking the sealed unions mentioned. Preferably, if not essentially, the elastic body of the member 4| is so organized in the assembly that it operates to maintain the collar portion 40 in snug running contact with the face of the stationary member 39, whereby a sealed engagement of the relatively rotatable portions 39 and 40 is maintained both when the pump is in operation and when it is idle. The member 4|, by virtue of its physical nature, is adapted to maintain such sealed engagement even though a slight misaligninent exists -between the relatively rotatable parts.

Having described the general construction of a pumpin which I have incorporated my present invention, attention will be directed to a consideration of the improvements in structure and structural organization that comprises the invention.

The pump impeller is of the double-vaned type, consisting in a disk-like body 5 that carries integrally on each of its opposite sides a set of curved vanes 50 (5| that may be of the form described in Letters Patent No. 2,165,892, granted to me July 11,` 1939. The liquid pumped enters from the inlet chest 3, through ports 8 and 9, into the radially inner ends of the involute passages formed between the vanes on each side of the impeller body. and under centrifugal effect the liquid flows outward through such passages into the outer periphery of the impeller chamber 4, whence it is forced into the outlet passage l2 and delivery line i4 of thepump. In order that the impeller shall operate with maximum hydraulic (or pneumatic) emciency, itis essential that the clearance between the edges of the impeller vanes and the inner surfaces of the side walls or wearing platesv I and Il of the impeller chamber shall be maintained at close tolerance. Thus, as in service wear occurs, the position of the edges of each set of vanes with respect to the associate wearing plate must be adjusted with nicety.

By virtue of the improvements of my invention the required adjustments may be effected readily and with precision. The adjustment of the impeller relatively to one of the wearing plates is effected from a point externally of the pump housing, while the adjustment of the other wearing plate relatively to the impeller is effected simply by removing an access member from the outer wall of the pump housing and adjusting a few screws. More particularly, in effecting an adjustment, the nuts 21 and 28 are loosened and the impeller shaft and the impeller are axially shifted, to bring the edges of the impeller vanes 5l into exactly the proper running clearance with respect to the wearing plate l0, which is rigidly secured in the wall of the impeller chamber 4. Then, the nuts are tightened on the bearing rings 23 and 24 to the extent necessary 4 to rotate under the torquev ofthe motor I5.'

Next, the wearing plate Il is moved into proper position of running clearance with respect to the edges of impeller vanes 50. To this end, means are provided for adjusting the wearing plate H axially yof the impeller. Such means comprise a plurality of screws 44 that are arranged at spaced-apart points in the circular extent of a flange Ila on the wearing plate. These screws pass freely through the flange into threaded engagement with the wall of the impeller chamber, and by tightening up on the screws the wearing plate is shifted towards the edges of the vanes 50 on the impeller. In order to limit the inward movement of the wearing plate, and to lock it in adjusted position, screws 45 are threaded in the flange l la and are arranged to bear upon the surface of the wall of the impeller chamber at points located between the spaced-apart screws 44. In manifest way, by the manipulation of the screws 44 and 45, the wearing plate Il may be brought into running proper position with respect rto the edges of thervanes 50, and then rigidly locked. Thus, proper clearance between the wearing plates land the edges of the vanes on the doubleacting impeller is established and maintainedv as need be.

It is important to note that the wall of the wearing plate Il may be effected. Indeed, the wearing plate Il, the impeller 5, and the wearing plate I5 may be removed from the pump' and replaced by new ones, all by virtue of the access aorded by removal of the member 48.

In modication means may be provided for adjusting the wearing plate Il without removing the access member. As shown in Figure 5, the wearing plate IIb may be equipped' with a threaded stem 48. and this stem may be engaged in a sleeve nut 49 that is adapted, when a lock nut 53 is loosened, to be rotated in its position in the wall of the pump housing, or as here shown, in the body of the access member 46a secured to such wall. Manifestly, by such means the wearing plate IIb may be adjusted relatively to the impeller without draining the pump and removing the access member. When an adjustment of the plate IIb has been made, the nut 52 is tightened, and the parts locked in adjusted positions. Thus, all of the adjustments for wear may be made without opening the pump housing. Of course, if renewal of parts is required the pump will be drained, and the access member 46a removed.

The threaded stem 48 is seured to the wearing plate lib by threaded engagement with a hub portion 53 integrated to the wearing plate body by means of one or more ribs 54, and the spaces 55 between the ribs provide the inlet for the entrance of the liquid being pumped to the vanes 50 of the impeller. In order that the wearing plate Hb shall not rotate when the nut 49 is rotated to effect a plate adjustment, the

n body of the plate is provided with a slot 56,

into which a key portion 51 in the impeller housing extends. In addition to the advantages already mentioned herein in behalf of the doubleacting impeller, it is important to note that the end thrust on the impeller shaft, created by the reaction of the uid being pumped-upon the impeller body, is in a single-acting pump pump housing 2 opposite to the wearing plate il is provided with a removable access member 46, which is normally held in sealed engagement with the wall, by means of screws 4l. The pump may be readily drained and the access member removed, and through the window thus opened in the pump wall the adjustment of the (a pump in which vanes are provided' on one side only of the impeller body) the proximate cause of substantial wear between rotating and stationary parts. my invention, the thrust created upon the impeller body is a double thrust, a thrust whose components are substantially equal in magnitude and effective in opposite directions. The undesirable consequences of end thrust are thus avoided.

The structure herein illustrated and described are exemplary of the various embodiments of the invention covered by the appended claims.

I claim as my invention:

1. A double-acting pump including an impeller chamber, an inlet chest extending on opposite sides of said chamber, an impeller mounted for rotation in said chamber, said impeller having vanes on its opposite sides, an outlet opening from such chamber, a combination inlet and wearing plate mounted in each of the opposite side walls of said chamber, means for securing said shaft in xed axial position while providing for intentional axial adjustment of said impeller to position the vanes on one of its sides in running clearance relatively to one of said plates, and means whereby the other of said plates may be adjusted in position of running clearance relatively to the vanes on the other side ofthe impeller.

2,. A double-acting pump including an impeller chamber, an inlet chest extending on opposite sides of said chamber, said chamber having op- In the double-acting pump of l ascissa posite side walls including inlets opening to said inlet chest, an outlet passage opening from said chamber, an impeller equipped with vanes on its opposite sides, a shaft extending into said chamber and mounting said impeller therein for rotation, two bearings for said shaft, a sealing device organized with one bearing for inhibiting the movement of fluid between the interior of the pump and the bearing, means organized with the other of said bearings for the axial adjustment of said shaft and impeller, whereby the edges of the vanes on one side of said impeller may be positioned with running clearance relatively to one of the inlet-providing side walls of the 1mpeller chamber, the opposite inlet-providing side wall of said impeller chamber being adjustable into position of running clearance relatively to the edges oi" the vanes on the opposite side of the impeller, and means for locking the last-named side wall in adjusted position.

3. A double-acting pump including an impeller chamber, an inlet chest extending on opposite sides of said chamber, said chamber provided with inlet and outlet passages, a combination inlet and wearing plate mounted in each of the opposite side Walls of said chamber, an impeller equipped with vanes on its opposite sides, a shaft extending into said chamber and mounting said impeller therein for rotation, two bearings for said shaft, a sealingdevice organized with one bearing for inhibiting the movement of uid between the interior of the pump and the bearing, means organized with the other of said bearings whereby said shaft may be axially adjusted to move the impeller and bring the edges of the vanes on one side thereof into position of running clearance relatively to one of said plates, the other of said plates being mounted for adjustment to bring it into position of running clearance relatively to the edges of the vanes on the other side of said impeller, and means for locking the last-named wearing plate in adjusted position. Y

4. A double-acting rotary pump including an impeller chamber having an inlet and an outlet, an impeller in said chamber, said impeller having vanes on each of its opposite sides, an impeller shaft extending into said chamber and having an end rotatably supporting said impeller, an inlet chest in said pump extending on opposite sides of said impeller chamber, each of the opposite side walls of said impeller chamber comprising a wearing plate cooperating with the vanes to form the outer surfaces of the fluid impelling passages between the vanes on the corresponding side of said impeller, said inlet to the impeller chamber comprising an opening in each of said wearing plates establishing communication between said inlet chest and the central region of said impeller chamber, and means for securing said impeller shaft in xed axial position while providing for intentional axial adjustment of the shaft.

5. A double-acting rotary pump including an impeller chamber having an inlet and an outlet, an impeller in said chamber, said impeller having impeller vanes on each of its opposite sides, an impeller shaft extending into said chamber and havingr an end rotatably supporting said-impeller, an inlet chest in said pump extending on opposite sides of said impeller chamber, the opposite side walls of said impeller chamber cooperating with the edges of the vanes to form the Outer surfaces of the fluid impelling passages between the vanes each of said side walls establishing communica' tion between said inlet chest and the central region of said impeller chamber, and means for securing said impeller shaft in fixed axial position while providing for intentional axial adjustment of the shaft.

6. A double-acting rotary pump including an impeller chamber having an inlet and an outlet. an impeller in said chamber, said impeller having impeller vanes on each of its opposite sides, an impeller shaft extending into said chamber and having an end rotatably supporting said impeller, an inlet chest in said pump extending on opposite sides of said impeller chamber, the opposite side walls of said impeller chamber comprising wearing plates that cooperate with the edges of the vanes to form the outer surfaces of the fluidimpelling passages between the vanes on the opposite sides of said impeller, means for effecting adjustment `of, one of -the wearing plates relatively to the edges of the impeller vanes with which it cooperates, said inlet to the impeller chamber comprising an opening in each of said side walls establishing communication between said inlet chest and the central region of said impeller chamber, and means for securing said impeller shaft in xed axial position while providing for intentional axial adjustment of the shaft.

7. A double-acting rotary pump including an impeller chamber having an inlet and an outlet, an impeller in said chamber, said impeller having impeller vanes on each of its opposite sides, an impeller shaft extending into said chamber and having an end rotatably supporting said impeller, an inlet chest in said pump extending on opposite sides of said impeller chamber, the opposite side walls of said impeller chamber cooperatng with the edges of the vanes on the opposite sides of said impeller, means for securing said shaft in xed axial position while providing for the axial adjustment of said shaft to move said impeller into position with the vanes on one of its sides in running clearance relatively to one of said side Walls, and means for adjusting the other of said side walls into position of running clearance with respect to the vanes on the other side of said impeller, said inlet to the impeller chamber comprising an opening in each of said side walls establishing communication between said inlet chest and the central region of said impeller chamber.

DANIEL MURPHY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

